DESCRIPTION (From the Applicant?s Abstract): This proposal focuses on the role of visual activity in the development of serial processing streams related to motion in cortex. A novel approach, developed in the sponsor?s laboratory, allows examination of ferret primary auditory cortex (A1) which is induced to receive visual information through the rerouting of retinal fibers in neonates. In these animals retinal axons are redirected to the medial geniculate nucleus (MGN) and through the intact thalamocortical pathway visual information is provided to A1. The proposed experiments will use optical imaging of intrinsic signals and single unit in vivo recordings to investigate the effects of visual activity on the representation of direction selectivity and the refinement of motion selectivity in the rewired auditory pathway. The degree of motion refinement from rewired A1 to subsequent stages of cortical processing, the anterior field (AF) and the ventral field (VF) will be compared to the degree of motion refinement in primary visual cortex and the secondary visual area, V2. Studies of the development of serial processing streams in the rewired auditory pathway may be relevant to understanding how processing streams develop in the normal visual cortex.